The essential habitat role of a unique coastal inlet for a widely distributed apex predator
Data files
Sep 19, 2023 version files 101.81 MB
Abstract
Essential habitats support specific functions for species, such as reproduction, feeding or refuge. For highly-mobile aquatic species, identifying essential habitats within the wider distribution range is central to understanding species ecology, and underpinning effective management plans. This study examined the movement and space use patterns of sevengill sharks (Notorynchus cepedianus) in Caleta Valdés, a unique coastal habitat in northern Patagonia, Argentina. Seasonal residency patterns of sharks were evident, with higher detectability in late spring and early summer and lower during autumn and winter. The overlap between the residency patterns of sharks and their prey, elephant seals, suggests that Caleta Valdés functions as a seasonal feeding aggregation site for N. cepedianus. The study also found sexual differences in movement behavior, with males performing abrupt departures from Caleta Valdés and showing increased roaming with the presence of more sharks, and maximum detection probability at high tide. These movements could be related to different feeding strategies between sexes or mate-searching behavior, suggesting that Caleta Valdés may also be essential for reproduction. Overall, this study highlights the importance of coastal sites as essential habitats for N. cepedianus and deepens our understanding of the ecological role of this apex predator in marine ecosystems.
README
The essential habitat role of a unique coastal inlet for a widely distributed apex predator
Access this dataset on Dryad https://doi.org/10.5061/dryad.fj6q5740p
Brief summary of dataset contents
Detection data, temperature data, tidal data and shapelines needed to reproduce all the analyses:
Shapefiles for Study Area: "Caleta_marea_alta.shp" and "Caleta_marea_baja.shp" are shapefiles representing our study area under varying tide conditions. We created these using QGIS and satellite imagery to support specific analyses. "GSHHS_f_L1_SouthAmerica.shp" is the shapefile delineating the broader South American region for reference.
Tidal Data: "Comodoro_2019-10-01_2021-03-31.txt" contains tidal data obtained from the nearest gauge station for the specified time period. The contents are self-explanatory.
Astronomic Tidal Predictions: "MADRYN_prediccion_2015-2016.txt" and "MADRYN_prediccion_2019-2021.txt" provide astronomic tidal predictions for the respective time periods. The contents are self-explanatory.
Depth Data: "Data_loggers.csv" includes depth data collected from data loggers deployed in Caleta Valdés. This data is integral to our research.
Sea Surface Temperature Data: "sst_2019-2021.csv" contains sea surface temperature data sourced from AquaMODIS for the study area during the specified timeframe. The contents are self-explanatory.
Acoustic Receiver Data: "Detections.csv" serves as the primary dataset, encompassing all detection data from the acoustic receivers placed in Caleta Valdés. Most columns are self-explanatory, with the exception of "TL_cm," which indicates the total length of individuals in centimeters. Receiver codes referenced in the paper figures can be found here.
These data files are crucial for replicating our analyses and findings. Further details on their usage can be found in the manuscript and accompanying code.
Code/Software
For the complete details and scripts used in our analyses, you can access the R code and associated resources on our GitHub repository at the following URL: https://github.com/Agustindewy/Sevengill_shark_telemetry
Methods
Detection data were collected via passive acoustic telemetry using VEMCO instruments.
Temperature and tidal data were downloaded from the web (see manuscript for sources).
Shapefiles are self-produced and downloaded from the web (see manuscript and R code for sources).
Usage notes
All analyses were perfomed using open-access R programming software.